Chrono HELP .204

[Got Juice?]

Well, I decided to chrono my pet load the other day. Decent accuracy, and although I concede that BLC2 meters a lot better for consistant throws, I prefer the cooler burning of H322 and it's more forgiving nature (+/- 4/10ths does not affect velocity or accuracy as much and a more gradual pressure curve).

Here is the spec load:
Vmax .40gr
Case: RP .204
Primer CCI Small Rifle Primer
Powder H322 24.8gr

Well, according to the book loads on Hodgdon's site, I should be seeing about 3500FPS

Here are the Chrono Results:
1 3922
2 3877
3 3861
4 3819
5 3872
6 3875
7 3580 (whoops, my bad I think I shorted a grain)
8 4019
9 3844
10 3910

Not as consistant as I would like, but theses are gopher loads, and my batch was done a little on the quick side, not hand trickling the last tenths like I would for maximum accuracy.

The question I have, is this normal? Bolt lift is fine, no pierced primers, no flattened primers, no cracked necks, no where near max load.
slight, very slight flowing around firing pin is it.

Gun is a Savage LRPV .920BBL unfluted SS

Comments or suggestions welcome.

Chrono was 10 yards from muzzle.

 

[ultimate_monkey]

Altitude , humidity, air density , riffle , barrel , chamber blah blah blah all come into play chrono have proper light ? Set up perfectly ? If your not showing any pressure signs I wouldn't be to worried about the velocity difference from the hodgdons site. The listed velocity is just what they got in their rifle on that givin day, I'd say chrono again and see if your results match what you just got

 

[Got Juice?]

Altitude , humidity, air density , riffle , barrel , chamber blah blah blah all come into play chrono have proper light ? Set up perfectly ? If your not showing any pressure signs I wouldn't be to worried about the velocity difference from the hodgdons site. The listed velocity is just what they got in their rifle on that givin day, I'd say chrono again and see if your results match what you just got

Setup was checked and verified with test ammo of a known velocity 3 times, then checked with .22 ammo, both match and club. Chrono was good.

I was a little concerned because there is no such thing as 'free', that and a whopping 400FPS gain over load data?

Temp was 16c, altitude is 890m, pressure was dead steady.

 

[rnbra-shooter]

Sounds like you validated your chono setup well.

10 _yards_ is unusually far for a chrono (10-15' is more typical), though there's nothing wrong with that (other than it making setup alignment a fussier affair).

It's almost as if your shot#7 was the only sensible figure you got, with the rest being ~350fps faster than expected.

What were your lighting conditions?
- clear sky or overcast?
- what time of day, or what sun position?
- diffuser screens used, or not?
- were the light sensors in sunlight or in shade?

.22 bullets are dark-coloured, dull-textured and blunt, highpower bullets are shiny and pointy. If the sun angle was such that you could have been getting a "glint" off the bullet, that could be an explanation.

 

[Got Juice?]

Sounds like you validated your chono setup well.

10 _yards_ is unusually far for a chrono (10-15' is more typical), though there's nothing wrong with that (other than it making setup alignment a fussier affair).

It's almost as if your shot#7 was the only sensible figure you got, with the rest being ~350fps faster than expected.

What were your lighting conditions?
- clear sky or overcast?
- what time of day, or what sun position?
- diffuser screens used, or not?
- were the light sensors in sunlight or in shade?


.22 bullets are dark-coloured, dull-textured and blunt, highpower bullets are shiny and pointy. If the sun angle was such that you could have been getting a "glint" off the bullet, that could be an explanation.

I oopsed on shot #7 it was a batch with a different COAL I first thought it was charge weight, But since pulling a bullet, charge weight was not changed, just the COAL.
Sky was overcast, perfect chrono conditions as the light was very flat.
TOD was 10:30 AM
Diffuser screens were in place, and of course being overcast, no sun on the sensors.

38Super IPSC ammo was used (Copper jacketed) of known velocity, then my .40 Major load with BDX Jacketed bullets, then the .22LR just to be sure that the chrono was validated before testing.

The only thing I was not able to do was run another string through the chrono that day, because the range got a little busy, and I had to share it with others oh well. Next time.

I don't think the gophers will care about the velocity